Gas valve with a thermoelectric safety device



Nov. 25, 1969 J. H. VAN DER ZEE 3,480,028

GAS VAIJVE WITH A THERMOELECTRIC SAFETY DEVICE Filed Feb. 5, 1967INVENTOR. JAN H. VAN DER ZEE ATTORNEY United States Patent 3,480,028 GASVALVE WITH A THERMOELECTRIC SAFETY DEVICE Jan H. van der Zee, Emmen,Drenthe, Netherlands, as-

signor to Honeywell Inc., Minneapolis, Minn., a corporation of DelawareFiled Feb. 3, 1967, Ser. No. 613,870 Claims priority, applicationGermany, Mar. 19, 1966,

Int. (:1. rzsn /24 US. Cl. 137-66 6 Claims ABSTRACT OF THE DISCLOSURE A100% safety shut-off and safe-lighting gas valve, having a manuallyresettable and thermocouple energizable latching mechanism for thesafety valve. In operation, a separate manual actuator is provided todeflect the latch and free the safety valve to close, without affectingthe position of the remainder of the latching mechanism that otherwisewould hold the valve open. The latching mechanism is such that thesafety valve cannot be manually opened by the manual resetting meansunless the latching mechanism is in its electrically released conditionor position, where the latch can engage and pick up the safety valve.

Background of the invention Valves, of the above-mentioned type; arebroadly old in the art. Examples of such valves may be seen in UnitedStates Patents Nos. 2,988,098 and 3,099,994. These valves were designedto meet the need for exceptionally safe, so called, safe-lighting meansfor gas burners. Older safe-lighting valves, once the heating system hadbeen put into operation, could be manually turned off (therebyextinguishing the pilot burner) and quickly turned on again (therebysupplying unburnt gas to the combustion chamber) before the thermocouplehad time to cool down enough to cause safety shut down. An effort toimmediately reignite the pilot burner, with gas having thus beensupplied to the furnace, occasionally resulted in a serious explosion.The above-mentioned patented devices and this invention cannot beoperated in that manner.

Brief summary of invention This invention is directed to a manuallyresettable and safe lighting gas valve with an axially movable safetyvalve or control member which is held open in the presence of a pilotburner flame and is closed in the absence of a flame by means of atemperature responsive safety device having a thermocouple energizablelatching mechanism. The latching mechanism in the gas valve permitsopening of the valve only when the safety device is de-energized. Aseparate manually operable means is provided to move the latch, to freethe valve from the latch of the latching mechanism, without changing theposition of the remainder of the latching mechanism. This simple andinexpensive combination provides the same fool-proof operation that themore complicated and more expensive prior art combinations provide.

Description of drawings FIGURE 1 is a sectional elevational view of thepreferred embodiment of the invention, in its closed position;

FIGURE 2 is a fragmentary sectional view showing the reset plunger orshaft in its depressed or resetting position;

FIGURE 3 is a view similar to FIGURE 2 wherein the reest plunger is inits retracted position and the safety valve is in its open position; and

3,480,028 Patented Nov. 25, 1969 "ice FIGURE 4 is a view similar toFIGURES 2 and 3 wherein the reset plunger is in its retracted position,the latching mechanism is being held by the thermoelectric means and themanually operable safety valve releasing plunger or shaft is depressedand is holding the latch plate and latch in their deflected 0r valvereleasing positron.

Detailed description The casing of the gas valve, shown in FIGURE 1, hasan inlet 2, a first outlet 4 for the main burner, and a second outlet 5for the pilot burner. Between inlet 2 and the outlets 4 and 5 andextending through the wall 3, is a chamber or bore 37, the upper planeof which provides a seat 38 for a closing member or interrupter valve 8and the lower plane of which provides a seat 36 for the closing memberor safety valve 6. Between seats 36 and 38 the chamber 37 connects withthe outlet 5 for the pilot burner (not shown).

The valve 6 has a coaxial bushing 18, on the free end of which is ashoulder or collar 17. Normally the bushing 18 is movably guidedpartially on the lower end of a manually operable resetting shaft orplunger 9 and partially on the upper end of an armature stem 10 which,in turn, is axially movable in a conventional thermoelectric safetyuntil 11. This unit is screwed into the casing 1 of the gas valve. Thesafety unit is adapted to be connected in a well-known manner to atherrnocouple (not shown) positioned to be heated by a pilot flame. Thearmature of the magnet (not shown) is secured to the lower end of thestem 10.

A generally L-shaped latching member 13 is rockably mounted in a groove19 in the stem 10 and is biased upwardly by a spring 12. A spring 7,positioned between the latching member and the valve 6, normally holdsthe valve 6 in its closed position against seat 36. Spring 12 is enoughstronger than spring 7 as to move a latch 14 on the latching member to aposition over the shoulder 17 when the armature is not being held by themagnet of the safety unit. An arm 15 projects laterally from thelatching member and into alignment with a manually operable trippingplunger 16. The upper end of this plunger is biased outwardly of thecasing 1 by spring 21 bearing against a knob 26. The plunger isgenerally parallel to the reset plunger 9, and is manually movable intoengagement with the arm 15 to deflect it to the position shown in FIGURE4 of the drawing, to free the latch 14 from engagement with the shoulder17. Spring 7 is then able to close valve 6 even if the latch is retainedby the magnet.

The resetting plunger for the valve 6 has a knob 29 on the outwardlyextending end thereof and carries an axially slidable interrupter valve8 intermediate its ends. A spring 22 nor-maly biases the knob to theretracted position shown in FIGURES 1, 3 and 4. The valve 8 ispositioned between two spaced abutments 23 and 24 on the plunger 9; andan O-ring seal and spring 25, between the valve and the abutment 23,normally holds the valve against abutment 24 but permits plunger 9 tomove relative to the valve 8 when the valve is seated on seat 38.

Operation Assuming that the gas valve, as illustrated in FIGURE 1, isinstalled in a heating system, the system may be placed in operation bydepressing knob 29. In so doing the lower end of the operating shaft 9acts on the upper end of the stem 10 and drives it against the force ofthe spring 12 into the safety unit 11. The armature, the latch and thevalve 6 are moved downwardly with stem 10 to their reset position. Thevalve 8 on the operating shaft 9 also moves downwardly to seat 38 forclosing the passage to the outlet 4 to the main burner. After closingseat 38,

the pressure on the knob 29 must be increased to overcome the force ofthe spring 25. The further pressure on the operating shaft 9, drives thestem to a position in which the latch 14 comes in contact with theshoulder 17 of bushing 18 of valve *6. By further movement, the latchmember, through the latch 14, takes the bushing 18 with valve 6 fromseat 36 to open the passage to the pilot burner through outlet 5, asshown in FIGURE 2.

After ignition of the pilot burner has been accomplished and anappropriate current from the thermocouple has energized the magnet ofthe safety unit 11, the armature and valve 6 will be held by saidmagnet. Now the knob 29 may be released, whereby the spring 22 returnsit with the connected plunger 9 to its retracted position. In thisoperation, the spring 22 moves the valve 8 from the seat 38 to open it.The gas can now flow from inlet 2, through the chamber 37 to outlet 5and to outlet 4, as shown in FIGURE 3.

The safety valve may be manually closed by depressing the knob 26 andmoving the plunger 16 against arm or extension of the latch plate 13 andpivoting it a suflicient distance that the hook of the latch 14disengages from the shoulder 17 on bushing 18 of valve 6. The spring 12is then free to move the valve upwardly against seat 36, as shown inFIGURE 4.

The plate 13 is provided with a central aperture, the diameter of whichis limited in a well-known manner by means of fixed parallel springwires (not shown) with a distance from each other corresponding to thediameter of the rod groove 19. With the elements in the position shownin FIGURE 4, an operating or resetting try, by depressing knob 29, wouldbe ineifecitve because the operating plunger 9 is not in abutment withstem 10, which is still being held by the armature, and latch 14 is notable to pick up valve 6.

After the magnet of the safety unit 11 is sufiiciently de-energized, thespring 12 will drive the plate 13 to the position shown in FIGURE 1. Thelatch, with its cam or sloped plane 28, pivots and slides in thisoperation on the shoulder 17 of the bushing 18 to again latch with thegas valve and be ready to be operated again.

The embodiments of the invention in which an exclusive property or rightis claimed are defined as follows:

1. In a gas valve having an inlet, a pilot burner outlet, a main burneroutlet, a normally closed safety valve for controlling gas flow to saidburner outlets, a normally open interrupter valve for controlling gasflow from said safety valve to the main burner, temperature responsivemeans for holding the safety valve open only when a pilot flame ispresent, a bodily movable latching means for detachably connecting saidtemperature responsive means and said safety valve, and manuallyoperable reset means movable on a longitudinal axis for closing theinterrupter valve and opening the safety valve and resetting saidtemperature responsive means; the improvement in said latching meanscomprising a first latch member operably connected to said temperatureresponsive means, a second latch member operably connected to saidsafety valve and detachably connectable with said first latch member,one of said latch members being pivoted about an axis normal to theaxis-of said reset means, means biasing said one of said latch membersaxially with respect to said reset means, said one latch member beingbiased to its latch engaging position by the same means that biases saidone latch member axially, and manually operable tripping means foractuating said one of said latch members to cause separation of saidlatch members to free said safety valve to return to its closedposition.

2. A gas valve as defined in claim 1 wherein said one latch member is agenerally L-shaped member having its base portion pivoted on thetemperature responsive means and the biasing means is a spring engagingsaid base portion.

3. A gas valve as defined in claim 2 wherein said interrupter valve,safety valve, manually operable reset means, latching means andtemperature responsive means are substantially coaxial.

4. A gas valve combination as defined in claim 1 in which the manuallyoperable means for tripping the latching means is separate from themanually operable means for resetting the safety valve.

5. A gas valve combination as defined in claim 1 in which the means fortripping the latching means is a reciprocable plunger spaced from andgenerally parallel to the safety valve resetting means.

6. A gas valve combination as defined in claim 5 in which said one latchmember has a cam surface thereon positioned for engagement with theother latch member for temporarily deflecting said one latch member assaid latch members move toward each other in a relatching operation.

References Cited UNITED STATES PATENTS 2,722,945 11/1955 Gresham 13766XR 2,962,036 11/1960 Collins 13766 2,988,098 6/1961 Thomas 251-67 XRBILLY S. TAYLOR, Primary Examiner US. Cl. X.R.

